Dental implants are surgically implanted in a patient's jawbone to provide anchors for prosthetic devices such as artificial teeth, crowns, bridges, dentures, and the like. Dental implants allow people who lose their teeth to be able to comfortably smile, speak, and chew.
Typically, the first step for installing an implant involves making an incision in the patient's gum or gingiva. Next, a hole or implant osteotomy is formed in the jawbone of the patient, which may involve widening pre-existing cavities, forming fresh osteotomies, or splitting the ridge and filling the voids with a synthetic bone material. The implant is then fixtured into the osteotomy.
The step of forming an osteotomy typically involves seven to ten drilling procedures of a prerequisite implant geometry to form a hole in the patient's jawbone, utilizing Xrays, CT-scan, and vital monitoring instrumentation. It may take half an hour to simply remove and reinstall drill bits in the surgical motor. This can be a difficult and time-consuming procedure and can cause discomfort and trauma for the patient, partially due to the pain, edema, and shock involved with the penetration of a relatively large drilling bit into the patient's jawbone. Bone necrosis, which may accompany the use of hand instrumentation (i.e., rongeurs, etc.), is also possible. Drilling in high bone densities can further exacerbate and complicate the osteotomy preparation.
The high rotational drilling speeds typically involved in the procedure can generate a significant amount of heat. High frictional forces and torques between the bone and the drilling bit can also result. Large amounts of heat can cause bone necrosis, and the high torque increases the risk of bone fracture and breakage of the drilling bit. Again, this adds to the trauma and suffering of the patient, and can inhibit the desired healing of the bone and osseointegration of the implant (Roberts W E, Turley P K, Brezniak N, et al., Bone Physiology and Metabolism, Calif Dent Assoc J., 1987:15:54-61; Brunski, J B, Biomechanial Factors Affecting the Bone-Dental Implant Interface, Clinical Materials, 1992:10:153-201).
In some cases, large dental counterbores are utilized to countersink the osteotomy for receiving a particularly configured large dental implant. Counterbores involve removal of bone material and can result in restricting vascularity and bone loss (Valen M and Locante W M, LaminOss Immediate-Load Implants: Part I-Introducing Osteocompression in Dentistry, J Oral Implantol, 26(3):177-184, 2000) or all of the abovementioned disadvantages.
Conventionally, a handheld osteotome is used to form an osteotomy in soft bone. Typically, an osteotome has a larger tip and is manually manipulated by the dental practitioner in an artful, uncontrolled osteocompressive fashion to dilate the soft, bony material. Again, using rotary drill bits and twist drills can result in some or all of the abovementioned disadvantages. Physically, drill bits and twist drills can laterally wander at the time of drilling at the intended osteotomy site, possibly resulting in damage to surrounding nerves, teeth, and/or other vital anatomical sites.
Often, the use of a crestal bone height reducer is required to cut uneven crestal bone to create a leveled implant osseous platform. The use of crestal bone height reducers involves removal of bone material and can cause some or all of the abovementioned disadvantages.
As indicated above, it can be difficult and time-consuming to effectively perform osteotomy preparation procedures with handheld instrumentation. It is also very important to minimize discomfort, trauma, and damage to the patient. Moreover, the drilling bits, counterbores, threadformers, and osteotome cutting tips are exposed to frictional forces and corrosive elements both in the patient's mouth and possibly during sterilization. In many cases, this results in these instruments needing frequent replacement, since wear and corrosion reduce their effectiveness.
Changing from one to another of these tools during surgery takes time from the oral surgeon, adds to the time the surgical site is open and exposed to oral bacteria, and extends the time the patient must be anesthetized. Changing from one to another of these tools also adds time to the implant procedure and cost due to equipment needed, and wear and tear on the surgical instrumentation.
Various inventions have been created to alleviate several of the aforementioned problems with the implant procedure. For example, U.S. Pat. No. 6,364,662 B1, issued to Ajay Kumar on Apr. 2, 2002 for DIAMOND-LIKE CARBON COATED DENTAL INSTRUMENT, describes a tool bit for preparing an osteotomy in the jawbone of a patient. In an effort to reduce the number of tools required to prepare an osteotomy, KUMAR's tool bit is a single tool comprising drilling and cutting bits, depth bands, and osteotomes, and is coated with a carbon coating/film. The tool bit may also be swapped out with other bits to accomplish the functions of threadformers, counterbores, and cutting tips.
The purpose of the carbon coating is to reduce the coefficient of friction between the tool bit and the jawbone, and improve the cutting performance. Some of the other benefits and advantages arise as a consequence of the coating properties of high mechanical hardness (wear resistance), corrosion resistance, and high thermal conductivity.
KUMAR's patent does not speak to an osteotomy locator or lateral osteotomy redirector, but instead has a distal tip composed of a multi-lobed, multi-planar tip. A multi-lobed, multi-planar distal tip will physically wander using a handheld instrument when function is initiated, making the precise location of the osseous implant site difficult.